A moving magnet type linear motor provided with a coreless or cored coil arranged on the side of a stator as well as a permanent magnet arranged on the side of a mover is widely applied, particularly as a driving source of a transportation mechanism with a long rail track, because it does not require expensive magnets arranged on the long rail track, and it does not generate heat nor need electric power provided on the mover side.
There are two types of moving magnet type linear motor. One is a two sided type in which a permanent magnet is arranged on both sides of the stator, and the other is a single side type in which the magnet is arranged only on a single side of the stator. In the two sided type linear motor, a perpendicular force generated between the stator and mover can be balanced out.
FIG. 5 shows a two sided type moving magnet type linear motor transporting goods/loads along a rail track on a base 8.
In this moving magnet type linear motor, a coiled body 80 comprising a plurality of coils arranged in a single direction is supported by a supporting member 81, and the coiled body 80 forms the stator. On the base 8, a yoke 9 with a U-shape cross section surrounding the coiled body 80 is movably supported by a wheel 93. Also, on the inner surface of the yoke 9, a plurality of permanent magnets 91, 92 are fixed opposing the sides of the coiled body 80 respectively. The yoke 9 and the plurality of permanent magnets 91, 92 form the mover (Japanese Patent Laid-Open No. 2005-86858, Japanese Patent Publication No. 3698585, Japanese Patent Publication No. 3478084, Japanese Patent Publication No. 3387324).
In the moving magnet type linear motor described above, a multiphase alternating current is applied to the coils forming the stator so that a shifting magnetic field is formed, thereby generating a thrust force on the mover in the same direction as the shifting magnetic field.
Therefore, in the moving magnet type linear motor shown in FIG. 5, a load is connected to the yoke 9 forming the mover so that the load can be transported in a single direction.